1. Field of the Invention
The present invention relates generally to apparatus and methods for providing percutaneous access to an internal operative site during a surgical procedure. More particularly, the present invention relates to a trocar system which can be percutaneously introduced while in a narrow-diameter configuration and which after introduction can be radially expanded to accommodate passage of larger diameter surgical instruments.
Minimally invasive surgical procedures rely on obtaining percutaneous access to an internal surgical site using small-diameter access tubes (typically 5 to 12 mm), usually referred to as trocars, which penetrate through the skin and which open to the desired surgical site. A viewing scope is introduced through one such trocar, and the surgeon operates using instruments introduced through other appropriately placed trocars while viewing the operative site on a video monitor connected to the viewing scope. The surgeon is thus able to perform a wide variety of surgical procedures requiring only several 5 to 12 mm punctures at the surgical site. Patient trauma and recovery time are thus greatly reduced.
Particular minimally invasive surgical procedures are often referred to based on the type of scope used to view the region of the body which is the operative site. Thus, procedures in the abdominal area, which rely on a laparoscope for viewing, are referred to as laparoscopic procedures. In such laparoscopic procedures, the patient's abdominal region is typically insufflated (filled with pressured carbon dioxide or nitrogen gas) to raise the abdominal wall and create sufficient operating space to perform a desired procedure. The trocars used in laparoscopic procedures must therefore include a valve at their proximal end to allow passage of the scope or surgical instruments while inhibiting leakage of the insufflating gas. It has also been proposed to perform laparoscopic procedures by mechanically expanding the abdomen rather than using insufflation.
Other minimally invasive surgical procedures include thoracoscopic procedures performed in the region of the chest, arthroscopic procedures performed in body joints, particularly the knee, gynecological laparoscopic procedures, and endoscopic surgical procedures performed in various regions of the body, typically with a flexible scope. These latter procedures do not normally employ pressurization and the trocars used generally do not include pressure valves at their proximal ends.
The design of suitable trocars must fulfill many requirements, particularly for those used in laparoscopic procedures in a pressurized environment. All trocars should be introducible to the patient with minimum trauma and with minimum risk of injury to internal organs. The trocars used in laparoscopic procedures should be readily sealable to inhibit the leakage of gas form the abdomen, and in particular should be designed to inhibit leakage in the region surrounding the external periphery of the trocar which passes through the abdominal wall. It is further desirable that trocars have means for anchoring within the percutaneous passage, and it would be particularly desirable if a single trocar could accommodate instruments having a wide variety of cross-sectional shapes and sizes.
Heretofore, trocar designs have met the above listed requirements with mixed results. The accommodation of various sized instruments has been met by providing trocars having different fixed diameters. Often, a surgeon will introduce the largest sized trocar, usually 10 to 12 mm, which can then accommodate most or all instruments (which are sized within this maximum) using a rubber adapter. While such an approach is feasible, the introduction of larger sized trocars exposes the patient to greater trauma and risk of injury than would be the case if smaller trocars were used.
External sealing about the periphery of the trocar has also not been adequately addressed. Certain trocar designs employ a tapered helical thread about their periphery. The thread is useful for anchoring, but greatly enlarges the trocar puncture in order to seal against the loss of pressurized insufflation gas. Other anchors, such as malecot structures have been employed on the distal end of the trocars, and are effective for anchoring but provide little sealing against the loss of pressure.
For these reasons, it would be desirable to provide trocars suitable for use in laparoscopic and other minimally invasive surgical procedures which can be easily introduced to the patient via a relatively small puncture (preferably less than 5 mm), which can then be radially expanded (and optionally subsequently reduced) to accommodate a wide variety of instrument sizes, and which provide for improved sealing about the trocar periphery and anchoring within the target site of the operative procedure.
2. Description of the Background Art
U.S. Pat. No. 5,183,464, assigned to the assignee of the present invention, describes a radially expandable dilator including an elongate dilation tube which receives an elongate expansion tube. European Patent Application 385 920 describes a variable diameter braid structure intended for capturing and removing stenotic material from blood vessels. U.S. Pat. No. 5,122,122, describes a trocar sleeve having a malecot structure at its distal end. Trocars for use in laparoscopic procedures are commercially available from suppliers such as United States Surgical Corp., Norwalk, Conn.; Endomed division of Cooper Surgical, Inc., Shelton, Conn.; and Dexide Inc., Fort Worth, Tex.
U.S. Pat. No. 4,738,666 describes an expandable catheter having an external sheath which is perforated to facilitate removal as the catheter is being expanded. U.S. Pat. No. 4,601,713, describes a variable diameter catheter having an inflatable retention balloon at its distal end. The catheter is introduced with an internal stylet which holds the catheter in a collapsed (reduced diameter) configuration. Removal of the stylet allows the catheter to expand. U.S. Pat. No. 4,141,364, describes an expandable endotracheal tube which is inserted in a collapsed configuration and springs back to an expanded configuration when air is introduced. Inflatable dilator apparatus are described in U.S. Pat. Nos. 4,589,868 and 2,548,602. Catheters having expandable structures are described in U.S. Pat. Nos. 4,986,830; 4,955,895; 4,896,669; 4,479,497; and 3,902,492.
U.S. Pat. No. 4,772,266, describes a dilator/sheath assembly that may be passed over an in-dwelling guide wire in order to enlarge an access hole, with entry of the sheath further enlarging the hole. U.S. Pat. No. 1,213,001, describes a trocar and cannula assembly which includes an intermediate tube to form a three-piece structure. U.S. Pat. No. 3,742,958, discloses a cannula having an axial slot to allow the cannula to be stripped from a working catheter which has been introduced through the cannula. U.S. Pat. Nos. 4,888,000; 4,865,593; 4,581,025; 3,545,443; and 1,248,492, each describe devices suitable for percutaneous penetration of a body cavity, blood vessel, or solid tissue. The disclosures of each of the U.S. patents cited in this paragraph are hereby incorporated herein by reference.
U.S. Pat. No. 4,899,729, describes an expansible cannula which includes a coiled conical sheath which can be percutaneously introduced and thereafter expanded by advancing an internal cylinder. U.S. Pat. No. 4,716,901 discloses an expandable trocar (not including a trocar valve) comprising a pair of opposed components having sharpened distal tips and covered by an elastic sleeve over a proximal portion thereof. U.S. Pat. No. 4,846,791, describes a multi-lumen catheter which includes an elastic outer sleeve and an internal divider which, when inserted, expands the sleeve. See also U.S. Pat. Nos. 668,879; 3,789,852; 4,411,655; 4,739,762; 4,798,193; 4,921,479; 4,972,827; 5,116,318; and 5,139,511, which were made of record in U.S. Pat. No. 5,183,464, assigned to the assignee of the present invention.
A dilator assembly including a guide member having an anchor at its distal end is described in copending application Ser. Nos. 07/616,122 and 07/913,129, assigned to the assignee of the present invention, the disclosures of which are incorporated herein by reference. A peel away sheath is described in copending application Ser. No. 07/967,602, assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference.